Noise of a Self-Sustaining Avalanche Discharge in Silicon: Low-Frequency Noise Studies

The noise theory for a self-sustaining avalanche discharge, which was published recently by Hines, is verified experimentally for low frequencies. It was found, in general, that the open-circuit spectral voltage density, 〈u2〉Av/Δf, arises from three contributions: (1) the inherent avalanche noise calculated by Hines and given by 〈u02〉Av/Δf = a2Vb2/I, where a2=3.3×10−20 A/Hz, Vb = breakdown voltage and I = avalanche current; (2) excess noise at low current densities caused by nonuniformities of avalanche breakdown (even in microplasma-free diodes); and (3) excess noise at high current densities which seems to be caused by thermal effects. The temperature dependence of the noise is entirely due to the two excess-noise contributions. The experimental results are discussed with respect to their application in the design of noise generators, low-noise and low-current avalanche diodes, microwave oscillators, and negative-resistance amplifiers.